Vernier dial attachment for machine tools



Nov. 23, 1954 L. A. SNOW VERNIER DIAL ATTACHMENT FOR MACHINE TOOLS Filed May 22, 1953 2 Sheets-Sheet 1 fiw 0%? FITTOR/VEV zmww Nov. 23, 1954 A. SNOW VERNIER DIAL ATTACHMENT FOR MACHINE TOOLS Filed May 22, 1953 2 Sheets-Sheet 2 IN V EN TOR. [Gm/70rd A. 600W am! (7M. 1

United States Patent VERMEER DIAL ATTACHRgENT FOR MACHINE TOOL Leonard A. Snow, Holliston, Mass. Application May 22, 1953, Serial No. 356,744 2 Claims. (Cl. 116115.5)

This invention relates to a vernier dial attachment for machine tools.

The invention has for an object to provide a novel and improved vernier dial attachment for machine tools for accurately indicating the position of a movable element of the machine tool.

Another object of the invention is to provide a novel and improved vernier dial attachment of the character specified having provision for adjustably stopping the movable element at a predetermined position whereby the movement of the movable element may be duplicated for successive pieces of work being worked upon.

With these general objects in view and such others as may hereinafter appear, the invention consists in the vernier dial attachment hereinafter described and particularlye defined in the claims at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention:

Fig. 1 is a cross-sectional view of the present vernier dial attachment showing the same applied to a cross slide of a lathe;

Fig. 2 is a plan view detail of the vernier dial attachment;

Fig. 3 is a front elevation of the same; I

Fig. 4 is a front elevation of a modified form of the present vernier dial attachment embodying stop means for terminating movement of the cross slide at a predetermined adjusted position;

Fig. 5 is a cross-sectional view taken on the line 55 of Fig. 4;

Fig. 6 is a plan view of the attachment shown in Fig. 4;

Fig. 7 is a cross-sectional detail view taken on the line 7-7 of Fig. 4 showing an adjustable stop clamp; and

Fig. 8 is a detail view of a pivoted stop member as seen from the line 88 of Fig. 5.

In general, the present invention contemplates a novel and improved vernier dial attachment for machine tools having a feed screw for advancing or retracting a slide on which a tool is mounted for performing cutting operations upon a piece of work, the attachment being herein illustrated as applied to the feed screw for the cross slide of a lathe. Some of the lathes now on the market are provided with relatively small diameter dials or gauges secured to the feed screw which are graduated in thousandths of an inch and are arranged to coact with a mark on a relatively stationary hub portion extended from the carriage. In practice, such dials are difficult to read because of the relatively small graduations necessitated by the small diameter of the dial.

In accordance with one feature of the invention, the relatively small dial may be replaced by a larger diameter dial secured to the feed screw, and a vernier section is arranged to be secured to the existing extended hub portion of the carriage which forms a bearing for the feed screw. The enlarged diameter of the present dial permits larger graduations in thousandths of an inch, which may be easily read, and the addition of the vernier permits readings in tenths of thousaudths of an inch, thus providing a vernier dial attachment for existing lathes permitting accurate and easily read measurements.

In a modified form of the invention and as illustrated herein, a plurality of movable and preferably pivotal stop members are provided on the stationary or vernier portion of the dial which may be selectively moved for cooperation with adjustable stop clamps provided on the feed screw dial whereby to permit repeat operations to be performed on successive pieces of work with uniform accuracy.

Referring now to the drawings and particularly to Fig. l, the present vernier dial attachment, indicated generally at 10, is herein shown as applied to the carriage 12 of a standard lathe wherein 14 represents the lathe bed and 16 represents the cross slide or tool carrying member of the lathe. The cross slide is arranged to be advanced or retracted by rotation of a feed screw 18 cooperating with a depending lug 20 of the cross slide.

As herein shown, the carriage 12 is provided with a relatively small diameter hub portion 22 extended therefrom and forming a bearing for the feed screw, and a vernier section or segment 24 having a relatively large radius and provided with a hub 26 may be adjustably clamped to the bearing portion 22 by a clamp screw 28, as shown in Fig. 3. A relatively large diameter dial 30, of a radius corresponding to the radius of the vernier section, may be keyed to the outer end of the feed screw 18 and may be provided with a handle 32 for rotating the same. The periphery of the dial 30 is graduated, as indicated at 34, preferably to provide one hundred digits or spaces, and the pitch of the feed screw 18 is such that rotation of the feed screw with the dial 30 through the angle of one such space effects movement of the cross slide 16 and the cutting tool mounted thereon one-thousandth of an inch. The stationary vernier section 24 is provided with a vernier scale indicated at 36 and is mounted adjacent the graduated edge portion 34 of the dial 30 to coact with the graduations thereof to permit adjustment in fractional increments, preferably of one ten-thousandth of an inch.

From the description thus far it will be seen that the present vernier dial attachment may be employed to replace the usual small diameter dial and may be easily attached or assembled on the existing carriage hub and feed screw of a standard lathe. It will be observed that the hub portion 38 of the dial 30, which is keyed to the end of the feed screw 18, extends within the bore 40 of the vernier hub, the bore being of a larger diameter than the hub 38 so that the bore does not form a bearing for the hub. In practice, the bore 40 may be varied to suit the diameter of the existing carriage hub 22.

In use the cross slide may be advanced to engage the tool with the work, and if desired, the vernier section 24 may be adjusted on its hub 22 to line up the zero position on the vernier with the zero or other key position on the dial. The tool may then be advanced by rotating the dial and feed screw the desired number of turns to obtain the diameter desired, the vernier permitting accurate readings to tenths of thousandths of an inch for accurate turning operations and for uniformly accurate repeat performances on successive similar pieces of work set up in the lathe.

Referring now to Figs. 4 and 5, a modified form of the attachment, embodying stop means, is also designed to be attached to the feed screw bearing portion 22 of a conventional small lathe. In the modified form of the invention, the vernier section 50 clamped to the hub 22 comprises a circular disk having a vernier scale 52 and provided with a plurality of spaced, radially arranged and preferably pivotally mounted stop members 54. The graduated dial 56, keyed to the end of the feed screw 18, is provided with a laterally extended rim 58 adapted to receive clamp members or dogs 60 which carry set screws 62 arranged to cooperate with the stop members 54 when the latter are rocked into the path thereof, as will be described. As herein shown, each stop member 54 is L-shaped, one end of the L being fitted in a radial slot 64 formed in the periphery of the vernier disk and rockingly mounted on a pin 66 secured therein. In the illustrated pivot structure, the pin 66 is first eX- tended through the stop member and is then inserted in a lateral groove 68 formed within the periphery of the disk with the pin coming to rest at the bottom of the lateral groove. The pin 66 may be held in place against the bottom of the groove by screws 70, one at each end of the groove, as shown, thus avoiding drilling through the periphery of the vernier disk. The pivot end of the L is rounded as shown and as thus assembled the free leg of the L stands upright when the stop is rocked in a clockwise or rearward direction as viewed in Fig. 5, and will lie horizontally when rocked forwardly or counterclockwise over the edge or periphery of the dial 56 Patented Nov. 23, 1954 screw 18 and carriage hub or feed and into the path of the set screws 62 carried by the clamping members 60.

As best shown in Fig. 7, each adjustable clamping member or dog 60 may comprise U-shaped members grooved at a radius such as to fit over the laterally extended rim 58 of the dial, the groove being made of a size such as to also receive a curved wear piece or clamping element 72 against which clamp screws 74 carried by the inner leg of the U may bear to clamp the member in its adjusted position on the rim. The outer leg of the U which extends over the periphery of the dial is provided with a radial lug or extension 76 in which the adjusting screw 62 is carried, the latter being maintained in its adjusted position by a set screw 78. One of the clamp members 60 may be provided with a handle 80, as shown, for rotating the dial.

In operation, the L-shaped stop members 54 are initially in their retracted position rocked out of the path of the set screws 62, and the feed screw 18 may be rotated by the handle 80 to present the tool against the work to be turned, whereupon the vernier disk 50 may be adjusted on its hub 22 to present the zero mark thereon in line with the zero mark on the dial 56. The tool may then be advanced to cut the rotating work by rotating the feed screw the required number of turns to reduce the diameter of the work to the desired amount, as indicated by the reading with relation to the vernier. One of the stop members 50 may now be rocked into operative position to dispose the same over the periphery of the dial, and an adjacent clamping member or dog 60 may then be loosened and adjusted along the rim 58 until its set screw 62 comes into engagement with the stop member, whereupon the clamp may again be tightened. Critical adjustment may be made by adjusting the set screw 62 in the clamp member 60. Now, the stop member 54 may be rocked to its inoperative position, and the feed screw may be rotated to retract the cross slide and the tool. In practice, the operator may count the number of rotations of the feed screw required to back the tool away from the finished work. Thereafter, when a new piece of stock has been set up in the lathe, for a similar or repeat operation, the

operator may rotate the feed screw to advance the tool toward the work the same number of turns he used to back away from the work, and during the final revolution he may rock the pivotal stop into operative position and then continue rotation of the feed screw until the set screw 62 engages the stop 54, thus permitting uniform and accurate repeat operations on successive pieces of work to be performed without further reference to the vernier.

The above description has been confined to a single cutting operation on each piece of work. However, it will be readily seen that the present stop arrangement may be employed with a cross slide provided with a double tool post wherein one tool engages the work when the cross slide is advanced and the other tool engages the work when the cross slide is retracted. Thus, in operation, one of the clamp members 60 may be adjusted relative to a stop member to limit the advancing stroke, and the other clamp member may be similarly adjusted relative to a stop member to limit the retracting stroke.

It will be further observed that the present vernier dial embodying stop means may be adjusted for a plurality of limiting or stopping positions in an advancing or retracting direction by virtue of the plurality of stop members and the plurality of adjustable clamping members, such plural stopping positions being of particular advantage when using a turret tool post having a plurality of cutting tools mounted thereon for successive use on a piece of work.

While the preferred embodiment of the invention has been herein illustrated and described, it will be understood that the invention may be embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:

1. A vernier dial attachment for a machine tool having a feed screw and having a relatively small diameter extended bearing portion for the feed screw, the attachment comprising; a vernier dial having a relatively large radius and provided with an elongated hub having a bore therethrough snugly receiving and clamped to said extended bearing portion and projecting a substantial distance beyond the end of said bearing portion, said vernier dial projecting radially from its hub at a position axially beyond said extended bearing portion, and a graduated dial having a radius corresponding to the radius of said vernier dial for cooperation therewith, said graduated dial having a hub portion extending within the bore of the hub of said venier dial and being fixed to said feed screw within the bore of the hub of said vernier dial.

2. A vernier dial attachment for a machine tool having a feed screw and having a relatively small diameter extended bearing portion for the feed screw, the attachment comprising; a vernier dial having a relatively large radius and provided with an elongated hub having a bore therethrough snugly receiving and adjustably clamped to said extended bearing portion and extending a substantial distance beyond the end of said bearing portion, said vernier dial projecting radially from its hub at a position axially beyond said extended bearing portion, a graduated dial provided with an axially extending flange at its periphery, said graduated dial being of a radius corresponding to the radius of said vernier dial for cooperation therewith and having a hub portion fixed to said feed screw within the bore of the vernier dial hub, at least one stop dog adjustably and removably clamped to said flange and having a stop screw adjustably mounted therein, and a pivotally mounted member carried by said relatively stationary vernier dial and selectively pivotally movable into the path of said stop screw for adjustably limiting the rotation of said feed screw.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 789,660 Keating May 9, 1905 1,235,437 Chard July 31, 1917 1,760,938 Edgar June 3, 1930 2,565,787 Tennant Aug. 28, 1951 

